Roger Federer has revealed that he anticipated a more competitive match against Leonardo Mayer in the US Open first round.

The five-time champion dropped just five games during a 77-minute rout, but the Swiss has insisted that he was concerned ahead of the contest at Flushing Meadows after Mayer had almost beaten him in Shanghai last year.

After the match, the 34-year-old said: "You never know how these matches are going to be played out. It looked like a very tough draw for me. The conditions were very different compared to when we played in Shanghai.

"The conditions here are faster, so better for me. Back then I might have been surprised by the way he was serving, this time I was ready for his big serves.

"Yesterday and today I was worried for the match. I had a feeling this was not going to be a good day. Plus I practised with him, so I wasn't too calm. I am happy now of the way it went and I am confident."

Federer is looking to secure his first title in New York since winning five in a row between 2004 and 2008.